The present invention relates to sheaves and more particularly to single or multiple groove sheaves having adjustable or variable pitch diameters and including adjustment and locking ring means.
Variable pitch sheaves of the type in which adjustment of relatively movable annular discoidal flanges are accomplished through an adjusting device coaxially located on a flange support hub are generally well known in the sheave art, attention being directed to the structural arrangement of an externally threaded nut threadedly disposed within an internally threaded nut which, in turn, is threaded to the end of a discoidal flange support hub, such arrangement being disclosed in U.S. Pat. No. 2,400,294, issued to D. Firth et al on May 14, 1946. Further attention is directed to U.S. Pat. No. 3,043,151, issued to H. R. Keepers on July 10, 1962, which teaches a variable pitch sheave which includes an adjustment ring and a locking ring with cap screws connecting the rings for joint rotary movement of the rings and to draw the rings together to effect a wedging and locking action between the ring threads and the threads on the hub. Finally, attention is directed to U.S. Pat. No. 2,633,031, issued to J. N. Browning on Mar. 31, 1953, which teaches a flattened hub and key arrangement; to U.S. Pat. No. 2,890,592, issued to H. R. Keepers on Jun. 16, 1959, which teaches aligning flanges, locking rings and hub keyways to receive keys and tightening screws passing through the locking rings and threaded in the flanges to cause the rings and flanges to clamp hub threads therebetween; and to U.S. Pat. No. 4,226,133, issued to M. S. Hanke on Oct. 7, 1980, which teaches a comparatively complex, cooperatively adjustable inner and outer hub means to support axially adjustable discoidal flanges with set screw means passing through aligned radial opening and slot means of the outer and inner hub means to engage a shaft extending through the inner hub means.
The present invention recognizing the comparatively large number of assembly parts required in these past arrangements and the comparative complexity in manufacturing and assembling such parts, provides a unique and novel adjustable sheave arrangement which is straightforward and economical to manufacture, assemble and maintain and which requires a minimum of parts both in single and multiple belt groove sheave arrangements. Further, the novel structure of the present invention permits for ready and easy adjustment of the sheave discoidal flanges and the enhanced locking of such discoidal flanges in a preselected position on a flange support hub to maintain a precise flange adjustment without the comparatively complex parts and tooling which has been required in the past.
Various other features of the present invention will become obvious to one skilled in the art upon reading the disclosure set forth herein.